Adsorption/Desorption Behavior Of Tetracycline Antibiotics In Soils

Tetracycline class of antibiotics?TCs? is widely used.lt has important significance theoretically and practically to explore the environment behavior of TCs in soil for environmental risk assessment and pollution control of antibiotics. The study chooses tetracycline ?TC? and chlorotetracycline?CTC? to explore the law of adsorption/desorption in soils and the influence of changing the factors?pH?cation strength?different cation?organic matter?.The results indicate below:?1?The secondary dynamics equation can fit to the adsorption dynamics process of TCs in soils well.The time of adsorption equilibrium of TC in two soils is 12h;the time of adsorption equilibrium of CTC in cinnamon soil is 2h,and that in black soil is 4h;The time of desorption equilibrium is 24h.?2?The adsorption capacity of CTC is stronger than TC.The Freundlich model can fit to the thermodynamic process of adsorption of TCs in soils well.?3?There is a two-way street in different pH.The adsorption capacity of CTC in soils gradually decrease with the increasing of cation strength.Under the condition of different cation,the 1gKf of CTC in soils is,in order,Mg²⁺<Ca²⁺<K⁺<Na⁺<NH⁴⁺. Without organic matter,the adsorption ability of CTC in soils is weakened.